GCr15轴承钢激光强化温度场及组织结构

The Temperature Field in Laser Transformation Hardening and Microstructures for GCr15 Steel Components

应用宽带扫描技术对GCrl5轴承钢进行激光强化处理实验,实测激光相变硬化区的硬度和深度。采用有限元软件对激光强化过程中的温度场进行数值模拟,数值模拟结果与实验结果符合较好。激光淬硬层显微硬度分布主要与激光加热时温度场分布有关,奥氏体化过程中渗碳体的溶解和奥氏体中碳的浓度决定了最终微观结构和表面硬度。表面温度高、奥氏体化时间相对较长及冷却速率快导致了表面的高硬度。表面最高温度接近熔化温度时,仍含有一定数量的未溶渗碳体。

The laser quenching of GCr15 steel by wide band scanning technology was researched. Hardness and depths of laser transformation hardening zones of samples were also measured experimentally. Temperature field in the laser hardening process was numerically simulated by MSC.Marc software. The calculated results are in good agreement with the experimental results. The distribution of microhardness is closely related to the temperature distribution made by laser heating process, Carbide dissolution and carbon diffusion have a considerable effect on the final microstructure and thus on the surface hardness. A high surface temperature, longer austenitization duration and the rapid cooling rates result in high surface hardness. But at the peak temperature near the temperatures of melting, a significant amount of undissolved carbides still exist in the surface.